1. Field of the Invention
This invention relates to systems for cutting sheet material and, more particularly, to a system employing two cooperating rollers to effect cutting of the sheet material.
2. Background Art
It is common in building construction to use studs made from sheet metal material. It is known to form cutouts in the sheet material to accommodate wiring, pipes, etc. These cutouts are commonly formed using hydraulic presses, air presses, etc. which form the cutout in a punching operation. Lines with these presses are known to run at speeds of 100 to 450 feet per minute, and at higher speeds with cutouts formed at longer intervals, i.e. on the order of 4 foot centers. Given the high demand for this type of stud in both the residential and commercial environments, increasing speed is an ever present goal for those designing sheet cutting systems.
It is known to use a roller pair with a cooperating punch and die arrangement to form a cutout in sheet material. In one form, a die opening is defined through one of the rollers to divert the cutouts to a space within the roller from where the cutout is removed before the next full revolution. The roller must thus be large enough to provide the cutout storage space and the path thereto from the point of cutting.
In one form, the invention is directed to a system for cutting sheet material. The system has a first roller with at least one cutting element thereon with the first roller rotatable around a first axis and the second roller having at least one receptacle thereon and rotatable around a second axis. The first and second rollers are relatively positioned so that as the first and second rollers rotate around the first and second axes, the one cutting element aligns with and projects into the one receptacle to thereby cause cutting out of a discrete portion of a sheet material between the first and second rollers. A servo drive is provided for at least one of a) rotating the first roller around the first axis and b) rotating the second roller around the second axis.
The first and second rollers cooperatively form a cutout from a sheet material. In one form, a biased pad on the second roller urges the cutout formed by the first and second rollers away from the second roller.
The bias pad may reside at least partially within the receptacle on the second roller.
The bias pad may be urged by at least one biasing element radially outwardly relative to the second axis. A plurality of coil springs may be used to produce the bias.
In one form, the cutting element has a cutting edge with a straight portion that is substantially coincident with a line extending radially from the first axis.
The receptacle is bounded by an edge. In one form, the edge has a straight portion that is substantially coincident with a line extending radially from the second axis.
A roll former/take up roll may be provided for advancing sheet material in a conveying direction between the first and second rollers independently of the first and second rollers.
In one form, a control is provided which senses movement of sheet material advancing in the conveying direction and coordinates rotation of the first and second rollers with movement of the sheet material in a predetermined manner.
The invention also contemplates a method of cutting sheet material, including the steps of: providing a first roller having at least one cutting element thereon and rotatable around a first axis; providing a second roller having at least one receptacle thereon and rotatable around a second axis; placing a sheet material between the first and second rollers; relatively rotating the first and second rollers to cause the one cutting element to project into the one receptacle and thereby form a cutout from the sheet material; and directing the cutout away from the second roller as an incident of the second roller rotating around the second axis.
The method may further include the step of providing a pad. The step of directing the cutout away from the second roller may include the step of repositioning the pad relative to the second roller to thereby move the cutout radially outwardly from the second roller relative to the second axis.
The invention may further include the step of providing a servo drive, with the step of relatively rotating the first and second rollers involving the step of at least one of a) rotating the first roller around the first axis and b) rotating the second roller around the second axis through the servo drive.
The method may include the step of advancing the sheet material in a conveying direction between the first and second rollers independently of the first and second rollers.
The method may further include the step of sensing movement of the sheet material advancing in the conveying direction and coordinating rotation of the first and second rollers with movement of the sheet material in a predetermined manner.
The step of coordinating rotation of the first and second rollers with movement of the sheet material may involve the step of one of a) stopping and b) varying the speed of rotation of the first and second rollers while allowing the sheet material to advance in the conveying direction at a predetermined speed for a predetermined time interval, and after the predetermined time interval one of c) rotating the first and second rollers and d) again varying the speed of rotation of the first and second rollers as sheet material is advanced in the conveying direction at the predetermined speed.
The invention is further directed to a system for cutting sheet material, which system has a first roller and a second roller, as previously described. The first and second rollers are relatively positioned so that as the first and second rollers rotate around the first and second axes, the one cutting element projects into the one receptacle to thereby form a cutout from a sheet material between the first and second rollers. The pad resides at least partially within the receptacle and urges a cutout formed by the first and second rollers away from the second roller.
The pad may be biased radially outwardly relative to the second axis as by a plurality of coil springs.
In one form, the pad resides at least partially within the receptacle and causes the cutout formed in sheet material by the first and second rollers to be urged out of the receptacle and separated from the second roller as the second roller rotates.
The invention is also directed to a system for cutting sheet material having a first roller and second roller, as previously described. The first and second rollers are relatively positioned so that as the first and second rollers rotate around the first and second axes, the one cutting element aligns with and projects into the one receptacle to thereby cut out a discrete portion of a sheet material between the first and second rollers. The cutting element has a cutting edge and the receptacle is bounded by an edge. At least one of a) a portion of the cutting edge is substantially coincident with a line extending radially from the first axis and b) a portion of the edge bounding the receptacle is substantially coincident with a line extending radially from the second axis.